[ns] max data to send with ftp

[Mirco Tegler]

Hello, 

is there a maximum of data, that be can send with ftp?

I simulate ftp and calculate the bandwidth with the proc recordftp.
The transfer time for 500Mbyte,1Gbyte and 2Gbyte looks ok, but if i send
3Gbyte, 4Gbyte or more i get the same transfer time for each of them.

Is there something like maxpkts or max transfer data that must be set ?
(for ftp ot tcp)

$ns at 1000.0   "$ftp0 send 500000000"  ;# 500Mbyte
$ns at 2000.0   "$ftp0 send 1000000000" ;# 1Gbyte
$ns at 3000.0   "$ftp0 send 2000000000" ;# 2Gbyte
$ns at 4000.0   "$ftp0 send 3000000000" ;# 3Gbyte
$ns at 5000.0   "$ftp0 send 4000000000" ;# 4Gbyte
$ns at 6000.0   "$ftp0 send 40000000000";#40Gbyte

proc recordftp {} {
        global sink0  f0 
        set ns [Simulator instance]
        #Set the time after which the procedure should be called again
        set time 0.25
        #How many bytes have been received by the traffic sinks?
        set bw0 [$sink0 set bytes_]
        #Get the current time
        set now [$ns now]
        #Calculate the bandwidth (in MBit/s) and write it to the files
        puts $f0 "$now [expr $bw0/$time*8/1000000]"
        #Reset the bytes_ values on the traffic sinks
        $sink0 set bytes_ 0
        #Re-schedule the procedure
        $ns at [expr $now+$time] "recordftp"
}


Best Regards,
Mirco